The fleet of Volotea, a Spanish low-cost carrier, consists exclusively of Boeing 717s. The carrier had the 5th-most 717s of any airline in the world as of May 7, 2014, according to Flightglobal's Ascend Online Fleets database. Volotea

In development now, this model shows what the Boeing's latest version of the 737 -- the 737-MAX -- will look like when it enters service. That's projected to be in 2016, but Boeing already has nearly 2,000 orders for this 737 variant. Stephen Brashear, AP

The 747-8, Boeing's latest variant of its iconic jumbo jet, takes off on its first flight on March 20, 2011. The variant helped ensure the fabled 747 would continue to be produced, at least for now. Ted S. Warren, AP

The 747 has even had a role in space travel. A modified 747 was used to help move the Space Shuttle between facilities on the ground. Here, the retired Endeavour spacecraft rides a 747 on Sept. 20, 2012. Shari Vialpando-Hill, via AP

Many of iconic-but-now-defunct airlines counted the 747 as one of their flagship planes. Among those was TWA, whose 747s are seen here at New York JFK Airport on Jan. 13, 1997. Ed Bailey, Associated Press

L'Avion was a French airline that tried using 757-200s for an all-business class product between Paris and New York. The venture launched in late 2006 but was bought in 2008 by British Airways and folded into its BA's similar OpenSkies unit. L'Avion

A Continental 757-takes off from Los Angeles on June 5, 2008. Many of Continental's 757s were incorporated into the fleet of merger partner United, now the second-biggest 757 operated in the USA. David McNew, Getty Images

This artist's concept provided by The Boeing shows the 777-9X, which -- along with the 777-8x -- is set to become the latest of the 777 variants. The planes aren't scheduled to be delivered to airlines until next decade. Boeing Graphic

An Air France 777 sporting the logo of the SkyTeam frequent-flier alliance. Air France was the world's No. 3 operator of 777s as of May 7, 2014, according to Flightglobal's Ascend Online Fleets database. Air France

Boeing is an aviation giant known across the world. From its iconic 747 jumbo jet to its workhorse 737 narrow-body aircraft to its new-age "Dreamliner," the company has delivered more than 10,000 aircraft to carriers across the planet. The jetmaker's lineup of commercial passenger jets are flying for carriers on all six inhabited continents.

Boeing still has five major jet models in production for passenger airlines, producing 737s,747s, 767s, 777s and 787s that ultimately are bound for airlines of all stripes and sizes. And two of the carrier's recently discontinued lines — the 717 and 757 — still have a major presence in the fleets of several airlines, especially in the USA.

Which airline is the world's biggest operator of Boeing's popular 777 wide-body? Who took delivery of Boeing's final 757? Scroll down for a snapshot look at those seven popular Boeing aircraft lines.

And be sure to check out our photo gallery, which includes seven iconic photos of each aircraft. The gallery kicks off with shots of the now-discontinued 717 and runs through Boeing's other modern models, ending with the company's revolutionary new 787 "Dreamliner" that made its maiden passenger flight in 2011.

Source: Aircraft information comes from Boeing. The aircraft tallies come from Flightglobal's Ascend Online Fleets database and were accurate as of May 7, 2014.

A snapshot of the Boeing's passenger jets that are flying for the world's airlines.